Extended benzodifuran e furan derivatives as example of p -conjugated materials obtained from sustainable approach
Chady Moussallem, Fr ed eric Gohier, Charlotte Mallet, Magali Allain, Pierre Fr ere
*LUNAM Universite, Universite d’Angers, MOLTECH-Anjou UMR CNRS 6200, SCL group, 2 Boulevard Lavoisier, 49045 Angers cedex, France
a r t i c l e i n f o
Article history:
Received 3 April 2012
Received in revised form 19 July 2012 Accepted 24 July 2012
Available online 1 August 2012
Keywords:
Conjugated materials Organic semiconductors Furan derivatives Green chemistry
a b s t r a c t
The synthesis of extended benzodifuranefuran systems are described as an example ofp-conjugated materials prepared by following a green approach with only water being produced as waste and using furan derivatives from renewable sources. Investigation of their optical and electrochemical properties shows that the new compounds present electronic properties compatible for application in organic electronics.
Ó2012 Elsevier Ltd. All rights reserved.
1. Introduction
The development of p-conjugated materials is motivated by their potential technological applications as organic semi- conducting materials for the fabrication of (opto)electronic de- vices, such as field-effect transistors (OFET), electroluminescent diodes (OLED) and photovoltaic cells.1e4The major goal in the de- velopment of organic-based electronic devices resides in the low cost process for their fabrication by using spin coating or inkjet printing.5e8 On the other hand, the flexibility of the organic chemistry allows the access to variousp-conjugated structures that can be tailored for the specific electronic or optical properties to optimize the performances of the devices.9e12
Although current organic photovoltaic cell technology repre- sents a promising clean energy production, it still falls short to consider the green criteria for the conception of the organic semiconductors. Indeed, the synthetic procedures of thep-conju- gated systems are essentially based on organometallic coupling reaction, such as Stille or Kumada couplings for the syntheses of oligo or polyheterocycles13e18or the use of Wittig or Wittig Horner reactions for building ethylenic bonds.15,19e22 Such synthetic pathways involve stoichiometric amounts of by-products, which require high degree of purification of the semiconducting materials.
Moreover, the resulting wastes are often toxic for the environment.
Nevertheless, possible alternatives consist in developing
conjugated structures via synthetic pathways, such as Knoevenagel condensation19,23,24or Schiff base reactions25e27leading only to water as waste. Hence, the formation of ethylenic or the iso- electronic azomethine bonds (eC]Ne) to lengthen the conjugated systems by clean reactions between aldehydes and carbanions or amines contrast with the Wittig or Wittig Horner reactions, which produce phosphine oxide or phosphate derivatives as waste.
In this context, we have focused on the synthesis via green chemistry approach ofp-donorsIaeccomposed of a benzodifuran moiety connected to furan units by azomethine junctions (Fig. 1).
The two steps of the synthetic pathway are based on condensation reactions giving only water as by-product. For these two steps, green solvents, such as ethanol or ethyl lactate were used and the purifications were done by precipitation and recrystallization.
O
O N
N F F
F F F
F F F
F F
O
O Ia-c
R
R Ia:R = H Ib:R = C5H11 Ic:R = CH2OC6H13
Fig. 1.Structure of the new conjugated derivativesIaec.
*Corresponding author. Tel.: þ33 241735063; fax:þ33 24173546305; e-mail address:pierre.frere@univ-angers.fr(P. Frere).
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Tetrahedron
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / t e t
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http://dx.doi.org/10.1016/j.tet.2012.07.079
Benzodifuran derivatives have been reported as hole trans- porting materials in organic electroluminescent cells28 or as electron-donor in organic solar cells29,30and several examples of conjugated materials based on azomethine have been described.31e34 Moreover furaldehyde and furyl alcohol used as starting materials are well known as renewable materials that are obtained by the dehydration of glucose or by transformation of lignocellulosic biomass.35e37 Organic semiconductors based on furan moieties have recently been evidenced in OFET and photo- voltaic cells.38e40
2. Synthesis
The synthetic pathway of compoundsIaecis shown inScheme 1.
Thefirst step involves a Michael addition between the carbanion of 2-perfluorophenylacetonitrile1and the benzoquinone2that affords after two intramolecular cyclisations the diaminobenzodifuran de- rivative3in 40% yield.41e43By using ethanol as solvent, the com- pound3rapidly precipitates in the mixture. It is easily isolated by filtration then washed with EtOH before using it for the next step with no more purification. The conjugated system has been ex- tended by the condensation of the two amino groups of3with an excess of aldehyde derivatives4aec (3 equiv). The condensation reactions are carried out in the presence of a little amount of P2O5(10% mol) in ethyl lactate as solvent. Ethyl lactate can be con- sidered as a green solvent miscible in water.44,45Addition of meth- anolewater (50/50 vol) mixture provokes the precipitation of compoundsIaecthat are obtained in 70e80% yields afterfiltration and washing with methanol. Excess aldehyde can be partially re- covered from the solution.
O
O
+ CN
F F F
F F
NH3,H2O
EtOH O
O NH2
H2N F F
F F F
F F F
F
1 2 F
3
3 +
R O CHO Ia-c
4a-c P2O5(10% mol.) Ethyl lactate
Scheme 1.Synthetic pathway ofIaec.
In order to increase the low solubility of the unsubstituted de- rivativeIa, pentyl or hexyloxymethyl chains have been introduced by using the aldehyde derivatives4bec, obtained, respectively in 85 and 70% yields by the sequence BuLi/DMF from5bec(Scheme 2).
The furan derivative5bis available while5chas been prepared in 75% yield by reaction of furyl alcohol with bromohexane in Aliquat 336 in the presence of KOH under microwave irradiation (t¼30 mn, T¼80C,P¼150 W).
3. X-ray structure of Ib
The crystallographic structure of single crystal ofIbobtained by slow evaporation of a chlorobenzene solution has been analyzed by X-ray diffraction. The compoundIbcrystallizes in the monoclinic P21/cspace group. As shown inFig. 2, the two azomethine bonds are coplanar with the central benzodifuran moiety and adopt an E configuration. The two lateral perfluorophenyl groups are not co- planar with the conjugated systems assuming a torsional angle of 55 with respect to the benzodifuran plane. The stacking of the molecules present an overlapping of the perfluorophenyl moieties with azomethine bonds and terminal furan units.46The distances between the planes of perfluorophenyl and furan cycles are close at 3.2A. On the other hand, molecules are also in contact through CeH/F interactions involving the hydrogen atoms of central ben- zene ring withdHeFdistances of 2.61A and the ones of terminal furans withdHeFdistances of 2.50A (Fig. S1in Supplementary data).
4. Theoretical calculations
In order to know the respective role of the pentafluorophenyl and iminoefuran groups on the electronic properties of com- pounds Iaec, theoretical calculations were performed at the ab initio density functional level with the Gaussian09 package by consideringIaecin a phase gas. Becke’s three parameters gradient- corrected functional (B3LYP) with a polarized 6-31G (d,p) was used for the geometrical optimization and for the HOMO and LUMO levels determination. In order to limit the computational calcula- tion time, pentyl or hexyl lateral chains ofIbandIbwere replaced by methyl group. The theoretical data are gathered inTable 1and the contours of the orbitals for the HOMO and LUMO levels ofIbare presented inFig. 3. The optimized structures ofIaecpresent a good planarity of the conjugated systems while the lateral penta- fluorophenyls units present a torsional angle of 49with benzo- difuran moiety. The torsion angle between the benzodifuran moiety and the perfluorophenyl groups are in agreement with the X-ray structure ofIb. It can be noted that the use of the geometry obtained from the X-ray structure to calculate the HOMO and LUMO energy levels for Ib led to difference inferior at 5%. The HOMO and the LUMO of compounds Iaec reside wholly at the conjugated backbones (Fig. 3). By comparison with compound3
Fig. 2.X-ray structure of compoundsIb.
O
HO +C6H13-Br Aliquat 336, KOH
microwave C6H13O O 5c
R O 5b-c
BuLi, DMF
Et2O R O CHO 4b-c
b: R = C5H11 c: R= CH2OC6H13
Scheme 2.Syntheses of aldehydes4bec.
Table 1
Calculated HOMO and LUMO levels and theoretical bandgapa
Compounds HOMO (eV) LUMO (eV) DETh(eV)
3 4.91 0.91 4.0
Ia 5.07 2.36 2.71
Ib 5.05 2.38 2.67
Ic 5.06 2.37 2.68
aB3LYP/6-31G(d,p).
that presents a HOMO level at4.91 eV, the replacement of the two amino groups by the electron withdrawing azomethine junctions leads to a slight stabilization of the HOMO for compoundsIaecat 5.0 eV. By contrast the LUMO levels ofIaecare strongly stabilized from0.91 eV for3to 2.37 eV forIaec, thus leading to a re- duction of the bandgap to reachz2.7 eV forIaec.
5. Electronic properties
The electronic properties of compounds3andIaechave been analyzed by cyclic voltammetry (CV) and by UVevis spectroscopy.
Electrochemical and optical data are gathered inTable 2.
The CV of3presents two reversible mono-electronic oxidation waves atEox1¼0.68 V andEox2¼0.82 V corresponding to the suc- cessive formation of a cation radical and a dication. By contrast for compoundsIaeconly one oxidation process is observed at around 1.2 V. As shown inFig. 4forIb, by increasing the scan rate in po- tential, the oxidation peak becomes reversible from a scan rate of 500 mV s1. For the reversible oxidation process at 500 mV s1the anodicecathodic peak separation is slightly inferior to 90 mV thus suggesting a mono electronic process leading to the formation a cation radical. Although no reduction process is observed for3, compounds Iaec present an irreversible reduction peak at Ered¼1.51 V. The more anodic oxidation for compounds Iaec compared to3and the access to the reduction state agree with the theoretical calculation that indicated the stabilization both of the HOMO and LUMO levels forIaec. Using an offset of4.99 eV for SCE versus the vacuum level and using the onset of the oxidation or reduction peaks leads to estimate HOMO and LUMO levels about 6.0 eV and3.6 eV for compoundsIaec.47The experimental data are lower than the computational data (Table 2) but it should be underlined that solvent effect was neglected in calculation. Nev- ertheless the gap between HOMO and LUMO levels calculated from computational or experimental data are very close with an elec- trochemical bandgap measured atDEelec¼2.5 eV.
Fig. 5displays the UVevis absorption spectra of compounds3and Ibin solution in CH2Cl2andfilm ofIbon glass. Compound3presents two absorption bands at 292 and 318 nm while compoundsIaec show a structured absorption band around 500 nm with the for- mation of three maxima. Vibronicfine structure in the absorption
band is the indication of a high degree of rigidification of the con- jugated chain due to the combination of the intrinsically rigid ben- zodifurane and the azomethine junctions. The lengthening of the conjugated systems leads to a strong batchromic shift corresponding Fig. 3.Frontiers orbitals of compoundIb.
Table 2
Electrochemical and optical data
Compounds Eoxa(V) Ereda(V) DEeleb(eV) lmaxc(nm) DEopd(eV)
3 0.68, 0.82 d d 318 3.9
Ia 1.22 1.51 2.5 452 2.6
Ib 1.18 1.51 2.5 469 2.4
Ic 1.20 1.51 2.6 461 2.5
a104M in 0.1 M Bu4NPF6/CH2Cl2, scan rate 100 mV s1.
b Electrochemical bandgapDEele¼EoxonsetEredonset.
c 104M in CH2Cl2.
d Optical bandgap calculated from the onset of the absorption band. Fig. 4.CV trace of compound Ib 5$104 mol L1 in 0.1 Bu4NPF6/CH2Cl2, top v¼100 mV s1; bottomv¼200 mV s1andv¼500 mV s1.
Fig. 5.Normalized absorption spectra of3andIbin solution in CH2Cl2andfilm ofIb deposited on glass.
to a decrease of the HOMOeLUMO gap from 3.9 eV for3to 2.5 eV for compoundsIaec. Films ofIbhave been deposited on glass by spin coating technique using chloroform as solvent. The UVevis absorp- tion spectrum of thefilm shows a broader and structured absorption band with the presence of three maxima at 512, 475 and 446 nm and a shoulder at 410 nm. Thefilm has been annealed till 130C without any UV spectrum modification indicating a good stability of thefilm.
For higher temperature, the intensity of the absorption decreases due to a degradation of thefilm.
6. Conclusion
In conclusion, we synthesized a new series of p-conjugated materials by following a green approach consisting in two sub- sequent condensation reactions, which give only water as by- products. The optical and electrochemical studies have shown that the combination of the benzodifuran and furan units via azo- methine junction leads to extended systems presenting electronic properties adapted for applications in organic electronics. On the other hand, the solubility of these compounds in common solvent is beneficial for developing devices via solution processable tech- niques, thus suggesting the interest of these compounds as semi- conductors materials. The preparation of photovoltaic cells with these materials, as well as analogues with longer conjugated chain, is now underway and will be reported in future publications.
7. Experimental section 7.1. General
NMR spectra were recorded on a Bruker Avance 300 (1H and19F:
300.1 MHz,13C: 75.7 MHz,T¼300 K). The spectra were referenced against the internal NMR-solvent standard. Chemical shifts were expressed in parts per million (ppm) and were reported as s (sin- glet), d (doublet), t (triplet), td (doublet triplet), m (multiplet) and coupling constantsJwere given in Hz. Mass spectra were recorded under EI mode on a VG-Autospec mass spectrometer or under MALDI-TOF mode on a MALDI-TOF-MS BIFLEX III Bruker Daltonics spectrometer. The main peaks are described according tom/z. The peak corresponding to molecular mass is expressed as (Mþ). IR Spectra were performed on a Bruker VERETEX 70. UV-visible op- tical data were recorded with a PerkineElmer lambda 19 spectro- photometer. HPLC solvents were used for the measurements.
Electrochemical experiments were performed with a Biologic SP150 potentiostat in a standard three electrodes cell using plati- num electrodes and a saturated calomel reference electrode (SCE).
1,4-benzoquinone 1, pentafluorophenylacetonitrile 2, 2-furyl alcohol, 2-furaldehyde 4aand 2-pentylfuran 4bwere purchased from Acros or Lancaster and used without further purification.
7.2. Preparation of precursors 3 and 5c
7.2.1. 3,7-Bis(perfluorophenyl)benzo[1,2-b:4,5-b0]difuran-2,6- diamine: 3. 2,3,4,5,6-Pentafluorophenylacetonitrile 2 (7.1 ml, 3 equiv, 55.5 mmol) was added to a solution of 1,4-benzoquinone 1 (2.0 g, 18.5 mmol) in ethanol (50 mL) at room temperature. Then addition of an excess of aqueous solution of ammoniac (7.0 mL) resulted in a fast exothermic reaction and precipitation of a white solid. After 1 h stirring the solid was recovered byfiltration and was washed with ethanol (25 mL). Drying under vacuum afforded 3.8 g (40%) of 3as a white powder, which was used in the next step without any further purification.
Mp: 260C.1H NMR (DMSO-d6): 6.98 (s, 2H), 6.68 (s, 4H) ppm
19F NMR (DMSO-d6):139.7 (dd, 4F,J¼6.8 Hz,J¼22.4 Hz),162.3 (t, 2F,J¼22.4 Hz),165.8 (td, 4F,J¼6.8 Hz,J¼22.4 Hz) ppm13C NMR (DMF-d7): 157.9, 146.9, 124.2, 108.7, 97.6, 75.5 ppm.
IR: 3110, 1481 cm1. Mass (MALDI-TOF):C22H6F10N2O2, Calcd 520.03 (Mþ), Found 519.4.
Anal. Calcd for C22H6F10N2O2: C, 50.70; H,1.15; N, 5.38. Found: C, 50.59; H, 1.40; N, 5.33.
7.2.2. 2-((Hexyloxy)methyl)furan: 5c. Furyl alcohol (0.156 mol, 13 mL), bromohexane (0.197 mol, 27.8 mL), KOH (0.23 mol, 12.9 g) and aliquat 336 (7 mL) were stirred in aflask adapted for micro- wave in open vessel. The mixture was irradiated under microwave till the temperature reached 80 C and this temperature was maintained for 30 min. Water was added to the mixture and the aqueous phase was extracted with diethyl ether. The combined organic phases were dried over MgSO4 and evaporated under vacuum. The crude mixture was purified by distillation with a Kugelroch apparatus under reduced pressure (P¼35 mbar, Toven¼105C) to afford5cas a colourless oil in 75% yield.
1H NMR (CDCl3): 7.40 (dd,1H,J¼1.8 Hz andJ¼0.9 Hz), 6.32 (m, 2H), 4.34 (s, 2H), 3.45 (t, 2H,J¼6.6 Hz), 1.58 (q, 2H,J¼7.5 Hz), 1.33 (m, 6H), 0.85 (t, 3H,J¼6.9 Hz) ppm13C NMR (CDCl3): 152.1, 142.5, 110.1, 108.9, 70.3, 64.6, 31.7, 29.6, 25.8, 22.6, 13.9 ppm. MS (EI):m/z¼182 (100%).
7.3. General procedure for the formation of aldehydes 4b and 4c
To a stirred solution of compounds5bor5c(0.04 mol) in dry ethyl ether (80 mL) at 10 C, was added dropwise n-BuLi (1.2 equiv). The mixture was stirred for 30 min at10 C and quenched with DMF (2.2 equiv, 3.2 mL). The mixture was allowed to warm to ambient temperature and was stirred for 4 h. An ammo- nium chloride solution (20 mL, 1 M) was added. The aqueous phase was then extracted with ethyl acetate. The combined organic layers were dried over MgSO4, filtrated, concentrated in vacuum and purified by column chromatography.
7.3.1. 5-Pentylfuran-2-carbaldehyde4b. Eluent for the chromatog- raphy: ethyl acetateecyclohexane (2e8).
Pale yellow oil, 5.81 g, 85% yield.
1H NMR (CDCl3): 9.51 (s, 1H), 7.16 (d, 1H,J¼3.3 Hz), 6.22 (d, 1H, J¼3.3 Hz), 2.71 (t, 2H,J¼7.5 Hz), 1.69 (m, 2H), 1.33 (m, 4H), 0.89 (t, 3H, J¼6.9 Hz) ppm13C NMR (CDCl3): 177.1, 164.3, 151.7, 123.9 (broad sig- nal), 108.7, 31.3, 28.4, 27.2, 22.3, 13.9 ppm. MS (EI):m/z¼166 (100%).
7.3.2. 5-((Hexyloxy)methyl)furan-2-carbaldehyde4c. Eluent for the chromatography: ethyl acetateecyclohexane (3e7).
Pale yellow oil, 6.3 g, 70% yield.
1H NMR (CDCl3): 9.52 (s, 1H), 7.14 (d, 1H,J¼3.3 Hz), 6.44 (d, 1H, J¼3.3 Hz), 4.44 (s, 2H), 3.43 (t, 2H,J¼6.6 Hz), 1.51 (q, 2H,J¼7.8 Hz), 1.25 (m, 6H), 0.80 (t, 3H,J¼6.9 Hz) ppm13C NMR (CDCl3): 177.8, 158.9, 152.5, 122.2 (broad signal), 111.0, 71.4, 64.9, 31.6, 29.5, 25.7, 22.5, 14.0 ppm. MS(EI):m/z¼210 (100%).
7.4. General procedure for the formation of Iaec
Aldehyde4aec(3 equiv, 0.57 mmol) and a catalytic amount of P2O5were successively added to a solution of3(100 mg, 0.19 mmol) in ethyl lactate (3 mL) at room temperature. After one night stirring, the solution was poured in 10 ml of wateremethanol. (50/50 vol) solution to give a precipitate. After filtration, the solid was re- covered, washed with methanol (30 mL) and dried under vacuum.
7.4.1. 2,6-N-Di[(furan-20-yl)carboxylimino]-benzo[1,2-b:4,5-b0]di- furan-3,7 pentafluorophenyl:Ia. Orange solid; yield 60%. The solu- bility is too low for allowing purification by chromatography or recrystallization.
1H NMR (CDCl3) saturation: 8.77 (s, 1H), 7.70 (d, 1H,J¼3.3 Hz), 7.43 (s, 1H), 7.14 (d, 1H,J¼3.3 Hz), 6.63 (m, 1H) ppm.
IR: 3115, 1487 cm1. Mass (MALDI-TOF): C32H10F10N2O4, Calcd 677.0 (MþþH), Found 676.6.
7.4.2. 2,6-N-Di[(50-pentylfuran-20-yl)carboxylimino]-benzo[1,2- b:4,5-b0]difuran-3,7-pentafluoro-phenyl: Ib.Recrystallisation from ethyl acetate solution, orange solid; yield 58%; Mp: 212C.
1H NMR (CDCl3): 8.64 (s, 2H), 7.35 (s, 2H), 7.03 (d, 2H,J¼3.6 Hz), 6.22 (d, 2H,J¼3.6 Hz), 2.73 (t, 4H,J¼7.5 Hz), 1.70 (q, 4H,J¼7.2 Hz), 1.36 (m, 8H), 0.91 (t, 6H,J¼7.0 Hz) ppm19F NMR (CDCl3):139.46 (dd, 4F,J¼6.8 Hz,J¼22.4 Hz),157.22 (t, 2F,J¼22.4 Hz),164.79 (td, 4F,J¼6.8 Hz,J¼22.4 Hz) ppm13C NMR (CDCl3): 163.4, 155.4, 150.8, 149.0, 145.7, 134.8, 127.3, 121.1, 109.2, 101.2, 31.4, 28.5, 27.3, 22.4, 13.9 ppm.
IR: 3120, 1491 cm1. Mass (MALDI-TOF): C42H30F10N2O4, Calcd 817.20 (MþþH), Found 816.8. Anal. Calcd for C42H30F10N2O4: C, 61.77; H, 3.70; N, 3.43. Found: C, 61.81; H, 3.64; N, 3.75.
7.4.3. 2,6-N-Di[(50(2-2-oxa-heptylfuran-20-yl))carboxylimino]-benzo [1,2-b:4,5-b0]difuran-3,7-pentafluoro-phenyl: Ic.Recrystallisation from ethyl acetate solution, orange solid; yield 65%; Mp: 210C.
1H NMR (CDCl3): 8.70 (s, 2H), 7.37 (s, 2H), 7.07 (d, 2H,J¼3.3 Hz), 6.51 (d, 2H,J¼3.6 Hz), 4.54 (s, 4H), 3.52 (t, 4H,J¼6.6 Hz), 1.60 (m, 4H), 1.29 (m, 12H), 0.88 (t, 6H,J¼6.9 Hz) ppm19F NMR (CDCl3):
139.53 (dd, 4F,J¼6.8 Hz,J¼22.4 Hz),158.82 (t, 2F,J¼22.4 Hz), 164.55 (td, 4F,J¼6.8 Hz,J¼22.4 Hz) ppm13C NMR (CDCl3): 158.0, 155.1, 152.1, 149.1, 146.0, 127.4, 111.7, 109.9, 101.4, 71.2, 65.1, 31.7, 29.6, 25.8, 22.6, 14.0 ppm. IR: 3121, 1492 cm1. Mass (MALDI-TOF):
C46H38F10N2O6, Calcd 905.3 (MþþH), Found 905.7. Anal. Calcd for C46H38F10N2O6: C, 61.06; H, 4.23; N, 3.10. Found: C, 60.68; H, 4.21; N, 3.18.
7.5. X-ray structure of Ib
X-ray single-crystal diffraction data were collected at 293 K on a BRUKER KappaCCD diffractometer, equipped with a graphite monochromator utilizing MoKa radiation (l¼0.71073A). The structure was solved by direct methods and refined onF2by full matrix least-squares techniques using SHELX97 package (G.M.
Sheldrick, 1998). All non-hydrogen atoms were refined anisotrop- ically and the H atoms were added by calculation and treated with a riding model. Absorption was corrected by SADABS program (Sheldrick, Bruker, 2008).
7.5.1. Crystal data for Ib. Red plate (0.460.390.05 mm3), C42H30F10N2O4, Mr¼816.78, monoclinic, space group P21/c, a¼15.6792(8)A,b¼12.1688(7)A,c¼10.5804(6)A,b¼108.048(4), V¼1918.4(2)A3,Z¼2,rcalcd¼1.413 gcm3,m(MoKa)¼0.124 mm1, F(000)¼836,qmin¼4.05,qmax¼27.54, 36,101 reflections collected, 4364 unique (Rint¼0.1247), restraints/parameters¼0/263, R1¼0.0675 andwR2¼0.1334 using 2144 reflections withI>2s(I), R1¼0.1656 and wR2¼0.1730 using all data, GOF¼1.037, 0.335<Dr<0.383eA3.
Crystallographic data excluding structure factors have been deposited with the Cambridge Crystallographic Data under refer- ence CCDC: 858095.
Acknowledgements
We thank Angers Loire Metropole for the fellowship accorded for the PhD of C.M.
Supplementary data
Copies of1H and13C and19F NMR of compounds3,4b,4c,5c,Ib andIc.Fig. S1presenting the packing ofIbin the crystal. Supple- mentary data associated with this article can be found, in the online
version, at http://dx.doi.org/10.1016/j.tet.2012.07.079. These data include MOLfiles and InChiKeys of the most important compounds described in this article.
References and notes
1. Pron, A.; Gawrys, P.; Zagorska, M.; Djurado, D.; Demadrille, R.Chem. Soc. Rev.
2010,39, 2577e2632.
2. Klauk, H.Chem. Soc. Rev.2010,39, 2643e2666.
3. Cheng, Y.-J.; Yang, S.-H.; Hsu, C.-S.Chem. Rev.2009,109, 5868e5923.
4. Mishra, A.; B€auerle, P.Angew. Chem., Int. Ed.2012,51, 2020e2067.
5. Arias, A. C.; MacKenzie, J. D.; McCulloch, I.; Rivnay, J.; Salleo, A.Chem. Rev.2010, 110, 3e24.
6. Mas-Torrent, M.; Rovira, C.Chem. Soc. Rev.2008,37, 827e838.
7. Walker, B.; Kim, C.; Nguyen, T.-Q.Chem. Mater.2011,23, 470e482.
8. Leong, W. L.; Mathews, N.; Tan, B.; Vaidyanathan, S.; Dotz, F.; Mhaisalkar, S.J.
Mater. Chem.2011,21, 5203e5214.
9. Roncali, J.Acc. Chem. Res.2009,42, 1719e1730.
10. Mishra, A.; Ma, C.-Q.; Bauerle, P.Chem. Rev.2009,109, 1141e1276.
11. Roncali, J.Macromol. Rapid Commun.2007,28, 1761e1775.
12. Kanibolotsky, A. L.; Perepichka, I. F.; Skabara, P. J.Chem. Soc. Rev.2010,39, 2695e2728.
13. Carsten, B.; He, F.; Son, H. J.; Xu, T.; Yu, L.Chem. Rev.2011,111, 1493e1528.
14. Zhou, H.; Yang, L.; Stuart, A. C.; Price, S. C.; Liu, S.; You, W.Angew. Chem., Int. Ed.
2011,50, 2995e2998.
15. Turbiez, M.; Frere, P.; Allain, M.; Videlot, C.; Ackermann, J.; Roncali, J.Chem.
dEur. J.2005,11, 3742e3752.
16. Hassan, J.; Sevignon, M.; Gozzi, C.; Schulz, E.; Lemaire, M.Chem. Rev.2002,102, 1359e1469.
17. Sheina, E.; Liu, J.; Iovu, M. C.; Laird, D. W.; McCullough, R. D.Macromolecules 2004,37, 3526e3528.
18. Tkachov, R.; Senkovskyy, V.; Komber, H.; Kiriy, A.Macromolecules 2011,44, 2006e2015.
19. Segura, J. L.; Martin, N.; Hanack, M.Eur. J. Org. Chem.1999, 643e651.
20. Jestin, I.; Frere, P.; Mercier, N.; Levillain, E.; Stievenard, D.; Roncali, J.J. Am.
Chem. Soc.1998,120, 8150e8158.
21. Frere, P.; Raimundo, J. M.; Blanchard, P.; Delaunay, J.; Richomme, P.; Sauvajol, J.
L.; Orduna, J.; Garin, J.; Roncali, J.J. Org. Chem.2003,68, 7264e7265.
22. Turbiez, M.; Frere, P.; Roncali, J.Tetrahedron2005,61, 3045e3053.
23. Ho, H. A.; Brisset, H.; Elandaloussi, E. H.; Frere, P.; Roncali, J.Adv. Mater.1996,8, 990e994.
24. Egbe, D. A. M.; Neugebauer, H.; Sariciftci, N. S. J. Mater. Chem. 2011, 21, 1338e1349.
25. Mealares, C.; Gandini, A.Polym. Int.1996,40, 33e39.
26. Guarin, S. A. P.; Bourgeaux, M.; Dufresne, S.; Skene, W. G.J. Org. Chem.2007,72, 2631e2643.
27. Barik, S.; Skene, W. G.Macromolecules2010,43, 10435e10441.
28. Tsuji, H.; Mitsui, C.; Sato, Y.; Nakamura, E.Adv. Mater.2009,21, 3776e3779.
29. Li, H.; Jiang, P.; Yi, C.; Li, C.; Liu, S.-X.; Tan, S.; Zhao, B.; Braun, J.; Meier, W.;
Wandlowski, T.; Decurtins, S.Macromolecules2010,43, 8058e8062.
30. Huo, L.; Huang, Y.; Fan, B.; Guo, X.; Jing, Y.; Zhang, M.; Li, Y.; Hou, J.Chem.
Commun.2012, 3318e3320.
31. Tshibaka, T.; Bishop, S.; Roche, I. U.; Dufresne, S.; Lubell, W. D.; Skene, W. G.
Chem.dEur. J.2011,17, 10879e10888.
32. Dufresne, S.; Bolduc, A.; Skene, W. G.J. Mater. Chem.2010,20, 4861e4866.
33. Sek, D.; Iwan, A.; Jarzabek, B.; Kaczmarczyk, B.; Kasperczyk, J.; Mazurak, Z.;
Domanski, M.; Karon, K.; Lapkowski, M.Macromolecules2008,41, 6653e6663.
34. Barik, S.; Bletzacker, T.; Skene, W. G.Macromolecules2012,45, 1165e1173.
35. Chheda, J. N.; Huber, G. W.; Dumesic, J. A.Angew. Chem., Int. Ed.2007, 46, 7164e7183.
36. Binder, J. B.; Raines, R. T.J. Am. Chem. Soc.2009,131, 1979e1985.
37. Hu, S.; Zhang, Z.; Zhou, Y.; Han, B.; Fan, H.; Li, W.; Song, J.; Xie, Y.Green. Chem.
2008,10, 1280e1283.
38. Gidron, O.; Dadvand, A.; Sheynin, Y.; Bendikov, M.; Perepichka, D. F.Chem.
Commun.2011, 1976e1978.
39. Woo, C. H.; Beaujuge, P. M.; Holcombe, T. W.; Lee, O. P.; Frechet, J. M. J.J. Am.
Chem. Soc.2010,132, 15547e15549.
40. Bijleveld, J. C.; Karsten, B. P.; Mathijssen, S. G. J.; Wienk, M. M.; de Leeuw, D. M.;
Janssen, R. A. J.J. Mater. Chem.2011,21, 1600e1606.
41. Obushak, M. D.; Martyak, R. L.; Matiychuk, V. S. Pol. J. Chem. 2002, 76, 1419e1424.
42. Caruso, H.; Panunzi, B.; Roviello, G. N.; Roviello, G.; Tingoli, M.; Tuzi, A.C. R.
Chim.2009,12, 622e634.
43. (a) Yi, C.; Blum, C.; Lehmann, M.; Keller, S.; Liu, S.-X.; Frei, G.; Neels, A.; Hauser, J.; Sch€urch, S.; Decurtins, S.J. Org. Chem.2010,75, 3350e3357; (b) Keller, S.; Yi, C.; Li, C.; Liu, S.-X.; Blum, C.; Frei, G.; Sereda, O.; Neels, A.; Wandloswki, T.;
Decurtins, S.Org. Biomol. Chem.2011,9, 6410e6416.
44. Pereira, C. S. M.; Silva, V. M. T. M.; Rodrigues, A. E.Green. Chem.2011,13, 2658e2671.
45. Bennett, J. S.; Charles, K. L.; Miner, M. R.; Heuberger, C. F.; Spina, E. J.; Bartels, M. F.; Foreman, T.Green. Chem.2009,11, 166e168.
46. Mallet, C.; Allain, M.; Leriche, P.; Frere, P.CrystEngComm2011,13, 5833e5840.
47. Cardona, C. M.; Li, W.; Kaifer, A. E.; Stockdale, D.; Bazan, G. C.Adv. Mater.2011, 23, 2367e2371.
